The car neds the motor and tranny in place and all the weight that would be in their location in place.This means that if you have the motor and tranny in,you can use sand bags or water containers to simulate the weight needed to do the measurements for the car.Same goes for the rear,put some thing in the rear to make the weight within reason.From their you can check how the diffy angle sits and measure it and check the tranny angles as well.Then you can measure the length needed for the driveshaft after pulling out the yoke a 1"-1.25,Mrmoaprtech